Tampon Having Spirally Shaped Grooves

ABSTRACT

A tampon for feminine hygiene, having an insertion end, a recovery end, a recovery tape, and a longitudinal axis. The tampon is made of compressed fibrous material and has an outer surface that is at least partially provided with spirally shaped, pressed longitudinal grooves. The grooves define spirally shaped longitudinal ribs. Also disclosed is a method for producing the tampon.

RELATED APPLICATION

This application is a continuation application of copending U.S. patentapplication Ser. No. 12/769,687, filed Apr. 29, 2010.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of copending U.S. patent applicationSer. No. 12/769,687, filed Apr. 29, 2010, which is a division ofcopending U.S. patent application Ser. No. 10/104,264 filed Mar. 22,2002, the disclosure of which is herein incorporated by reference. Thisapplication claims priority of German Patent Application No.10114786.4-45, filed Mar. 26, 2001, the disclosure of which is hereinincorporated by reference.

FIELD OF THE INVENTION

The invention relates to a tampon for feminine hygiene having pressed,spiral grooves.

BACKGROUND OF THE INVENTION

State of the art tampons and methods and equipment for their manufactureare disclosed in Leutwyler, et al., U.S. Pat. Nos. 5,911,712, 5,813,102,and 5,832,576. The tampon has an insertion end, a recovery end with arecovery tape, and a central section extending between the insertion endand the recovery end. It has a compressed, generally cylindrical, solidfibrous core, from which relatively uncompressed longitudinal ribsextend radially outward. Each rib is separated from adjacent ribs in thevicinity of the compressed fiber core to an extent which is greater thanthat extent to which such a rib is separated from an adjacent ribremotely from the compressed fiber core. Further, the fiber core can bepressed more strongly in the central area than in the area of therecovery end of the tampon. The recovery end of the tampon can also beprovided with a finger recess and the insertion end with a round dome.Finally, the tampon is at least partially surrounded by aliquid-permeable sheathing.

Such a tampon can be formed with the following steps: rolling up alength of a continuous fibrous web to form a generally cylindricaltampon blank with a circumferential surface; simultaneous radialpressing of narrow, strip-shaped sections of the circumferential surfaceof the tampon blank arranged in a spaced manner to form a number oflongitudinal grooves which are separated from one another by relativelyuncompressed longitudinal ribs which extend radially outward from arelatively compressed core, the core being compressed to a smallerextent in the area of the recovery end of the tampon than in itsremaining area; and pressing of outer ends of the longitudinal ribsradially inward to form a soft, smooth circumferential surface, whilethe relatively uncompressed fibrous structure of the ribs is preserved.Furthermore, a finger recess and a round dome can be provided at therecovery end and the insertion end of the tampon respectively. Lastly, aliquid-permeable sheathing is fixed on the fibrous web at least inparts, so as to provide a liquid-permeable layer on at least part of theouter surface of the tampon blank.

The formation of the grooves and ribs of this state of the art tamponare known from these disclosures and that of Friese et al., U.S. Pat.No. 6,310,269, which provides a tampon, especially useful as a digitaltampon, that has a densified central core and a softer outer surface.

While this tampon represents a significant improvement over thepreviously commercialized tampons, there remain areas susceptible toimprovement. One such improvement that is desirable is increased surfacearea to reduce the likelihood of early leakage of fluids flowing downthe surface of the tampon.

Patent literature has also suggested that coiled tampons can be formedfor improved flexibility (such as disclosed in Brecht, U.S. Pat. No.3,011,495, and Schirmer et al., U.S. Pat. No. 2,965,101) and for easierwithdrawal (such as disclosed in Shimatani, U.S. Pat. No. 4,328,804, andSneider, U.S. Pat. No. 4,351,339). These coiled tampons are generallyformed by twisting one or more “ropes” of material. However, theseimprovements in flexibility and withdrawal characteristics appear toresult in reduced column strength.

The object of the invention is to improve the tampon, the method and theapparatus as described above in such a manner that the risk of leakageafter the tampon has been put into use is reduced considerably byextending the time over which the tampon absorbs body fluid, and byenlarging the surface of the tampon and increasing the fiber quantityavailable for immediate absorption of body fluid after the introductionof the tampon, in particularly preferred embodiments in the area of thefiber core.

SUMMARY OF THE INVENTION

The invention achieves this object by virtue of a tampon for femininehygiene having an insertion end, a recovery end, and a longitudinalaxis. The tampon is made of compressed fibrous material having an outersurface. The outer surface of the tampon is at least partially providedwith spirally shaped, pressed longitudinal grooves. The tampon ispreferably compressed radially with respect to the longitudinal axis. Itcan have an essentially uniform density over a cross-section of thetampon, or it can have a core of highly compressed fibrous material fromwhich core longitudinal ribs extend radially outward. The longitudinalribs are thus defined by the spirally shaped, pressed longitudinalgrooves.

As a result of the longer distances the body fluid has to cover onaccount of the spiral design of the longitudinal ribs and of the spirallongitudinal grooves extending between these along the surface of thetampon, and as a result of the associated longer dwell time of theliquid in the spiral longitudinal grooves, the absorption and expansioncapacity of the tampon is utilized in a considerably better manner.

The invention also provides a method of producing a tampon. The methodincludes providing a tampon blank of tangled fibrous material; andcompressing the tampon blank and at least partially forming spirallyshaped longitudinal grooves at the outer surface of the tampon in orderto enlarge the absorbent surface of the tampon. Preferably, the tamponblank is radially compressed with respect to the longitudinal axis onnarrow lines of its circumferential surface. Again, the tampon blank canbe compressed to provide an essentially uniform density over thecross-section of the tampon, or it can provide a core with a high degreeof compression, from which relatively uncompressed longitudinal ribsextend radially outward.

One embodiment of the tampon of the present invention can bemanufactured using an apparatus for producing a tampon. The apparatushas a press having press jaws of substantially equal dimensions whichare arranged in a star formation with respect to the press axis. Thejaws can be moved synchronously in a common plane radially with respectto the press axis between their open position and closed position. Intheir closed position, the jaws can support one another on theirmutually opposite longitudinal sides. Each press jaw has a steppedpressing surface wherein the pressing surfaces of the press jawspreferably form a press opening of round cross section with a length inthe range from 40 to 70 mm. In addition, each pressing surface has apressing blade, which is oriented toward the press opening, and apressing shoulder, which is arranged only on a specific side flank ofthe pressing blade and in each case is oriented in the samecircumferential direction about the press axis. The pressing shoulder isoffset to the outside in relation to the press axis with respect to apressing edge at the free, inner end of the pressing blade, and the areaof the pressing shoulder is greater than the pressing edge of thepressing blade of each press jaw. The pressing surface, including thepressing blade and the pressing shoulder, is spirally shaped.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is described in greater detail below with reference to thediagrammatic drawing of illustrative embodiments of the tampon and ofthe apparatus for implementing the method of producing the tampon, inwhich:

FIG. 1 shows a tampon with spiral longitudinal ribs and longitudinalgrooves according to the invention in a perspective illustration;

FIG. 2 shows the measurement of a circumferential angle α of a spirallongitudinal groove on a tampon according to the invention in aperspective illustration, taken from the rear end;

FIG. 3 shows a tampon with spiral longitudinal ribs and longitudinalgrooves according to another embodiment of the invention in aperspective illustration;

FIG. 4 shows a cross section of the tampon in FIG. 2 along the lineII-II;

FIG. 5 shows an apparatus for producing tampons according to FIGS. 3 and4 in a partly sectioned side view;

FIG. 6 shows a cross section through a pressed fiber body or preform ina press along the line IV-IV in FIG.

FIG. 7 shows the front side or inlet side of the press, which is shownin the open state with a tampon blank and in the closed state of thepress jaws with a preform;

FIG. 8 shows the press according to FIG. 7 in the closed state;

FIG. 9 shows a press jaw in a rear view;

FIG. 10 shows a perspective rear and side view of the press jaw in FIG.9;

FIG. 11 shows the press in the pressing dimension with a preformarranged in it, the circumferential surface of which is curved in abarrel-shaped manner, in a central longitudinal section;

FIG. 12 shows the press in an illustration similar to FIG. 11 but in theclearance dimension, with the preform arranged in it, thecircumferential surface of which is substantially cylindrical;

FIG. 13 shows a press with divided press jaws in the pressing dimensionin a central longitudinal section;

FIG. 14 shows the press in FIG. 13 in the clearance position of thepress jaws for ejection of a preform;

FIG. 15 shows a perspective view of the inlet side of a final shapingtool;

FIG. 16 shows a detail XIII of FIG. 5 on larger scale with a view of atampon, and

FIG. 17 shows a detail Z of FIG. 16 in a greatly enlarged illustration.

DETAILED DESCRIPTION OF THE INVENTION

According to one embodiment of the present invention, FIG. 1 illustratesa tampon 30 for feminine hygiene, having an insertion end 32, a recoveryend 34, a longitudinal section 36 having a longitudinal axis L and lyingtherebetween, and a recovery tape 35. The tampon 30 preferably consistsof a radially compressed fibrous material.

The outer surface of the tampon 30 is at least partially provided withlongitudinal ribs 40 defined by pressed longitudinal grooves 42. Thelongitudinal ribs 40 are spirally or helically shaped in the axialdirection between the insertion end 32 and the recovery end 34 andpreferably extend over at least about 80° of the tampon circumference.However, the circumferential angle a can, depending also on thedimensions of the tampon, be selected in the range of up to at least150°, preferably in the range of 80° to 120° of the tampon 30. Thenumber of longitudinal ribs 40 can vary, for example depending on thediameter of the tampon and/or the type of absorption material.Preferably, there are at least about four ribs, and more preferably, atleast about six. While the present invention, like many known tampons,my have an even number of ribs, it is also possible to produce tamponsaccording to the present invention with an odd number of ribs.

These tampons may be produced in accordance with the general teaching ofFriese et al., U.S. Pat. No. 6,310,269, and Leutwyler et al., U.S. Pat.No. 5,832,576, the disclosures of which are herein incorporated byreference. These apparatus and methods disclosed in these references aremodified, as described below, to form the tampons of the presentinvention. In addition, the tampons having pressed spiral grooves mayalso be produced in accordance with the general teaching of Neipmann etal., U.S. Pat. No. 2,798,260, and Wolff et al., U.S. Pat. No. 3,422,496,the disclosures of which are herein incorporated by reference. Again,these apparatus and methods disclosed in these references can bemodified according to the general principles described below to formother embodiments of the tampons of the present invention. Inparticular, the individual press jaws and components can be formed inthe spiral manner as described hereinbelow.

As shown in FIG. 2, the spiral longitudinal grooves 42 defining theseribs 40 can each extend over a circumferential angle α of up to at least150° of the tampon. FIG. 2 also shows that the fibrous material of thetampon 30 can have an essentially uniform density over the crosssection.

As mentioned above, the spiral grooves 42 enlarge the surface of thetampon and provide longer distances for the body fluid to traversebefore leakage around the tampon occurs. This improvement can resultsfrom any depth of groove. However, it is preferred that the groove has adepth of at least about 1 mm. In the embodiment discussed below inregard to FIGS. 3 and 4, the groove may have a depth of more than about4 mm, preferably about 4 mm to about 6 mm.

Preferably, the ribs are separated from adjacent ribs proximate the coreto an extent which is greater than that extent to which such a spiralrib is separated from an adjacent spiral rib remotely from the core.

In the embodiment of FIGS. 3 and 4, the tampon 30 has a compressed,central, solid, generally cylindrical fiber core 38 with a high degreeof compression, which ensures the stability or column strength of thetampon 30 during digital introduction of the tampon 30 into a bodycavity. The longitudinal ribs 40 are relatively uncompressed and have,in particular on a circumferential surface 46 of the tampon 30, a softfibrous structure. The longitudinal ribs 40 extend radially outward atequal circumferential angle intervals from this solid fiber core 38. Asshown in FIG. 4, the spiral longitudinal ribs 40 are separated from oneanother by corresponding spiral longitudinal grooves 42 at leastproximate the fiber core 38. According to a further embodiment of theinvention, however, the circumferential surface of the tampon and itsfiber core can also be substantially cylindrical with a circularcross-section, or even an oval cross-section.

In a more preferred embodiment, the longitudinal grooves 42 are closed,at least at the circumferential surface 46 of the tampon 30, as the sideflanks 44 of adjacent longitudinal ribs 40 touch one another to form thesoft, closed circumferential surface 46 of the tampon 30. Thiscircumferential surface 46 of the tampon 30 makes possible more gentleand therefore more pleasant introduction of the tampon 30 into the bodycavity and a high absorption capacity of the same.

As a result of the fact that the outer ends lying against one another ofthe side flanks 44 of adjacent longitudinal ribs 40 close thelongitudinal grooves 42 only at the circumferential surface 46 of thetampon 30, the longitudinal grooves 42 form in each case eight closedspiral guide ducts 50 (FIG. 4) which are in each case preferably openonly at the insertion end 32 and at the recovery end 34 (the openings atthe insertion end 32 are visible in FIG. 3). These guide ducts 50 eachhave a drop-shaped cross section which is largest at the fiber core 38and tapers radially outwardly to the place in which the adjacentlongitudinal ribs 40 lie against one another with the radially outerends of their side flanks 44. Immediately after the introduction of thetampon 30 into the body cavity, these spiral guide ducts 50 convey thebody fluid to the fiber core 38 also, in order to utilize its fibrousmaterial immediately to increase the absorption capacity and expansioncapacity of the tampon 30 and to accelerate the opening of the closedguide ducts 50 radially outwardly. Therefore, the arrangement of thespiral longitudinal ribs 40 and the spiral guide ducts 50 orlongitudinal grooves 42 brings about an enlargement of the surface ofthe tampon 30 and consequently an extension of the dwell time orabsorption time for body fluid, which results in the absorption capacityand expansion capacity of the fiber core 38 being improved considerably.At the same time, a reduction in the weight of fibrous material used inthe tampon 30 is thus possible, which allows more economical productionof the tampon 30.

The recovery end 34 of the tampon 30 is, as is known per se, providedwith a finger recess 48, which facilitates the insertion of a finger toexpand the recovery end 34 and to subsequently introduce the tampon 30and accelerates the expansion of the tampon 30. For this purpose, theinsertion end 32 of the tampon 30 also has a round dome 52, the outeredge of which is smoothed or chamfered. As the approximatelyhemispherical dome 52 has a relatively short length, the spirallongitudinal ribs 40 and spiral longitudinal grooves 42 can extend overan optimum length of the tampon 30.

The tampon 30 has an approximately circular diameter in the range from 6to 17 mm, the compressed, approximately cylindrical fiber core 38 havinga diameter of up to 5 mm. The tampon 30 is preferably at least partiallysurrounded by a liquid-permeable sheathing, which is known per se andtherefore not shown. An example of this is disclosed in Friese, U.S.Pat. No. 4,816,100, the disclosure of which is herein incorporated byreference. This sheathing can consist of, for example, an airlaidnonwoven covering material made of tangled, at least in partthermoplastic, heat-sealing fibers or of a perforated plastic film (suchas a three-dimensional apertured film), or the like. In particular whennonwoven covering material is used for the tampon sheathing, it isrecommended that the circumferential surface 46 of the tampon 30 issmoothed, which can, if appropriate, be carried out with the applicationof heat. Such a sheathing improves the comfort of introduction andprevents fibers being detached during introduction or removal of thetampon 30 into or from the body cavity. Finally, the tampon 30 can bemore weakly radially pressed in the area of its recovery end 34, so thatthe fibrous material there is less strongly compressed and the expansionof the fibrous material at the recovery end 34 before introduction ofthe tampon 30 is made easier.

According to an advantageous embodiment of the invention, thecircumferential surface of the tampon and its fiber core can be curvedin a barrel-shaped manner. As a result of the associated lowercompression of the fibrous material over the entire cross section of thetampon in the area of its barrel-shaped convexity, not only the fibrousmaterial in the form of the spiral longitudinal ribs surrounding thesolid fiber core, but also the in contrast relatively greatly compressedfibrous material of the fiber core, can, when acted on by body fluid,expand more rapidly and moreover absorb a greater quantity of liquid.

Preferably, the tampons are formed predominantly of fibers. A useful,non-limiting list of fibers includes, cellulosics, polyester, polyvinylalcohol, polyolefin, polyamine, polyamide, polyacrylonitrile, and thelike, and they may have any useful cross-section, including multi-limbedand non-limbed. A useful, non-limiting list of cellulosics includesnatural fibers such as cotton, wood pulp, jute, hemp, sphagnum, and thelike; and processed materials including cellulose derivatives such asregenerated cellulose (including rayon), cellulose nitrate,carboxymethyl cellulose, and the like. Multi-limbed, regeneratedcellulosic fibers have been commercially available for a number ofyears. These fibers are known to possess increased specific absorbencyover non-limbed fibers. Commercial examples of these fibers are Danufil®VY multilimbed viscose rayon fibers available from Acordis Ltd.,Spondon, England. These fibers are described in detail in Wilkes et al,U.S. Pat. No. 5,458,835, the disclosure of which is hereby incorporatedby reference.

The tampons preferably contain at least a certain quantity of fibers,for example 25%, which are stiffer or more resilient than previouslyconventional fibers. Such resilient fibers include the Danufil® VYfibers and consequently have a considerably increased memory effect,which increases the absorption capacity of the tampon 30, and polyesterfibers.

A preferred apparatus according to the invention for producing thetampon comprises:

-   -   a press having press jaws of equal dimensions which are arranged        in a star formation with respect to the press axis x and can be        moved synchronously in a common plane radially with respect to        the press axis x between their open position and closed position        and, in their closed position, are supported on one another on        their mutually opposite longitudinal sides;    -   a stepped pressing surface on each press jaw,    -   the pressing surfaces of the press jaws forming a press opening        of round cross section with a length in the range from 40 to 70        mm;    -   each pressing surface having a pressing blade which is oriented        toward the press opening, and a pressing shoulder, which is        arranged only on a specific side flank of the pressing blade and        in each case is oriented in the same circumferential direction        about the press axis x, the pressing shoulder being offset to        the outside in relation to the press axis x with respect to a        pressing edge at the free, inner end of the pressing blade, and        the area of the pressing shoulder being greater than the        pressing edge of the pressing blade of each press jaw, the        pressing surface in each case consisting of the pressing blade        and the pressing shoulder on each press jaw being spirally        shaped.

As FIG. 5 shows, an apparatus 60 for producing the tampon 30 describedabove consists of a number of elements arranged coaxially one behindanother, namely a feed and ejection device 62, a star-shaped press 64with press jaws 66 which have pressed a preform 84 in their closed orpressing position, a final shaping tool 68 and a circulating or rotatingtransport apparatus 70. The transport apparatus 70 is, for example, arevolver 72, to which transport sleeves 74 are fixed at equalcircumferential angles and radii. The revolver 72 can be moved step bystep, so that the transport sleeves 74 can be moved successively infront of the outlet end of the final shaping tool 68 to receive in eachcase a finished tampon 30 ejected from the final shaping tool 68 by thedevice 62.

The feed and ejection device 62 according to FIGS. 5 and 12 is known perse and consists of a feed pusher 76 which can be moved to and frocoaxially with respect to a press opening 78 of the press 64. The feedpusher 76 has a circular face 80 with a diameter which correspondsapproximately to that of a tampon blank 55 (FIG. 7), preferably of awound blank, by means of which face the tampon blank 55 can betransferred coaxially into the opened press 64. A bar-shaped ejector 82is mounted displaceably to and fro relative to the feed pusher 76coaxially inside the feed pusher 76, the diameter of which ejector issmaller than the press opening 78 in the raised position of the pressjaws 66. The ejector 82 serves for, in a single operation, transferringone preform 84 pressed in the press 64 through the final shaping tool 68into one of the transport sleeves 74 of the revolver 72. In the finalshaping tool 68, the preform 84 then takes on the final shape of thefinished pressed tampon 30 described above.

FIG. 6 shows a cross section of the preform 84 in the embodiment of FIG.5. It can be seen that the cross section of the longitudinal ribs 40 iswidened radially outwardly in a drop-shaped manner to thecircumferential surface 46 of the preform 84. In contrast, thelongitudinal grooves 42 extend radially inwardly in a cross-sectionallydrop-shaped manner to the fiber core 38, so that they are wider at thefoot of the longitudinal ribs 40 than in the area of the circumferentialsurface 46 of the preform 84.

According to FIGS. 7 and 8, a preferred press 64 consists of eightidentical press jaws 66 which are arranged in a star formation in acommon plane at equal angle intervals about and at the same radialdistance from the press axis x. It is desirable to equip the press withan even number of press jaws, but other numbers of press jaws can beused, including odd numbers. The number of press jaws 66 can vary, forexample depending on the weight and the composition of the materialintended for the tampon 30, and can also be smaller or greater thaneight, although the number generally should not be under four. The pressjaws 66 have the same dimensions and can be moved to and frosynchronously radially with respect to the press axis x between theiropen position and closed position (see FIG. 7). In the closed orpressing position, the press jaws 66 are in each case supported on oneanother on their mutually opposite side walls 86, 88, as is explained ingreater detail below.

FIGS. 7 and 8 show the inlet side of the press 64, the press jaws 66 ofwhich are illustrated in the opened and in the closed position in FIG.7. Each press jaw 66 has a jaw foot 108 with three through-holes 110 forfixing elements (not illustrated) on guide strips (not illustrated).

The profile of the press jaws 66, which can be seen in the front view ofthe press 64 in FIGS. 7 and 8, extends essentially on that side of alongitudinal mid-axis y of each press jaw 66 which is orientedcounterclockwise, in an L-shaped manner from the jaw foot 108 to thepress opening 78. The profile of each long L-leg 112 is tapered radiallyin a triangle-like manner toward a short L-leg 114 and, after thistaper, merges at its radially inner end into a striking head 116 (FIG.7) which has a rounded profile and is a component of the strengthenedshort L-leg 114 which is angled in the clockwise direction as comparedwith the long L-leg 112. This angling is in the form of a strikingrecess 118, the round cross-sectional profile of which extends over anarc of approximately 90° in the direction of the press opening 78 andcorresponds to the cross-sectional profile of the striking head 116 ofthe press jaw 66 adjacent in the clockwise direction. The end of theshort L-leg 114 lies at a small distance from the press jaw axis y andforms a pressing blade 92.

A longitudinal mid-axis z of the profile of the pressing blade 92 formswith the longitudinal mid-axis y of the associated press jaw 66 an angleα/2 which in each case opens counterclockwise in relation to thelongitudinal mid-axis y of the press jaw 66. This angle α/2 between thelongitudinal mid-axis z of the pressing blade 92 and the longitudinalmid-axis y of the press jaw 66 in FIGS. 7 and 8 corresponds to half thecircumferential angle α/2, that is to say 60° in the present case, withwhich each longitudinal groove 42 extends spirally over thecircumferential angle of 120° about the press axis x. It follows fromthis that the profile of the other, rear end (not visible in FIGS. 7 and8) of the same press jaw 66 is curved in the clockwise direction ascompared with the front press jaw profile visible in FIGS. 7 and 8, orencloses an angle with the longitudinal mid-axis y of the press jaw 66concerned which opens in the clockwise direction in FIGS. 7 and 8 andcorresponds to the second half circumferential angle α/2 of 60° of theoverall circumferential angle α of 120°.

In the long L-legs 112 of the press jaws 66, a blind hole 111 is in eachcase arranged in the vicinity of the pressing blade 92 for receiving aheating element. The blind holes 111 are positioned in the best possiblemanner in order to bring about optimum heating of each press jaw 66. Thetemperature of the press jaws 66 is in the range from 80° C. to 120° C.and is regulated by means of electronic pulses while observing as smallas possible a tolerance range. Each press jaw 66 has its own temperaturesensor. The thermal insulation of each press jaw 66 consists of asynthetic material made by the company Ensinger GmbH, 71154 Nufringen,Germany, which is resistant to high temperature and high pressure orcompressive force. By heating the press jaws 66, it is possible toreduce the memory effect of modern, highly absorbent, greatly expandingfibrous materials, which occurs after the tampon 30 has been finished.By means of the heated press jaws 66, the surface of the tampon 30 issimultaneously smoothed during pressing and pushing out, and aqualitatively improved surface is produced even in tampons of lowweight, the stability of the tampon 30 being preserved. The memoryeffect of the fibrous material becomes effective again when the fibrousmaterial of the tampon 30 is wetted with body fluid.

FIGS. 9 and 10 show more clearly that each press jaw 66 has an effectivepressing surface 90 which is stepped. These pressing surfaces 90 form apress opening 78 of round cross section with a length in the range from40 mm to 70 mm. Each pressing surface 90 has a pressing blade 92 whichis oriented toward the press opening 78, and a pressing shoulder 96which is arranged only on a specific side flank 44 of the pressing blade92, that is to say is in each case oriented in the same circumferentialdirection about the press axis x. The stepping is brought about byvirtue of the pressing shoulder 96 being offset to the outside inrelation to the press axis x with respect to a pressing edge 94 at thefree, inner end of the pressing blade 92. Furthermore, the area of thepressing shoulder 96 is greater than that of the pressing edge 94 of thepressing blade 92 of each press jaw 66. At the same time, the pressingsurface 90 consisting of the pressing blade 92 and the pressing shoulder96 on each press jaw 66 is spirally shaped. The pressing blade 92 andthe associated pressing shoulder 96 of each press jaw 66 can extend overa circumferential angle α of up to at least 150° in the closed orpressing position of the press 64, with a diameter of the press opening78 in the range from 8 to 17 mm. For the press jaws 66 of the presentillustrative embodiment, which are formed in one part, a circumferentialangle α of the pressing blade 92 and of the pressing shoulder 96 of eachpress jaw 66 of 80° to 150°, 120° in the present case, is preferred.

According to a preferred feature of the present invention, the pressjaws 66, when in a pressing position d in FIG. 11, touch an imaginarybarrel-shaped envelope surface 104 with their substantially spiralpressing surface 90. In the pressing position, the pressing blade 92 ofeach press jaw 66 is oriented essentially although not exactly radiallywith respect to the press axis x (FIGS. 7 and 8). The spiral pressingblades 92 and spiral pressing shoulders 96 of all the press jaws 66,when in a clearance position d+ in FIG. 12, each touch an imaginary,substantially circularly cylindrical envelope surface 106. In thisconnection, the diameter of the cylindrical envelope surface 106 of theclearance dimension d+ of the press jaws 66 corresponds at least to thegreatest diameter of the barrel-shaped envelope surface 104 of thepressing dimension d of the press jaws 66. As a result, improvedejection of the preform from the press is achieved, the high surfacequality of the pressed fiber body thus being preserved.

Moreover, the 0° vertex of the arcuate curvature 102 of the spiralpressing surface 90 lies on the longitudinal mid-axis y of each pressjaw 66. The pressing surface 90 extends toward its two ends incomplementary fashion in each case over half a circumferential angle α/2in the range of up to at least 75° of the spiral pressing surface 90 ofthe press jaw 66. This situation is explained in greater detail below.

The cross section of the pressing blade 92 is drop-shaped, the greatestthickening lying behind the front, narrow, rounded pressing edge 94, anda neck-like contraction 122 being present toward a pressing blade foot95. The pressing shoulder 96 is arranged eccentrically with respect tothe pressing blade 92, in each case only on one specific side surface oftwo side surfaces 98, 100 of the pressing blade 92 (FIG. 9). Thisspecific side surface 98 or 100 of all the press jaws 66, which adjoinsthe pressing shoulder 96, is in each case uniformly oriented only in theclockwise direction or counterclockwise. In FIGS. 7 and 8, which showthe front side of the press 64, this side surface 98 of the pressingblade 92 facing toward the pressing shoulder 96 is in each case orientedcounterclockwise. In this connection, each pressing shoulder 96 isoffset to the outside radially in relation to the press axis x withrespect to the narrow pressing edge 94 of the pressing blade 92 by theradial distance between the fiber core 38 and the circumferentialsurface 46 of the preform 84, and has in the circumferential directionof the press opening 78 a greater area than the pressing edge 94 of thepressing blade 92. The center of curvature of the pressing shoulders 96of all the press jaws 66 then lies on the axis x of the press 64 only inthe clearance position d+ of the press jaws 66.

According to FIGS. 9 and 10, which show the end face of a press jaw 66at the rear or outlet side of the press 64, the pressing shoulder 96 is,in contrast, oriented in the clockwise direction. The pressing surface90, consisting of the pressing blade 92 and the pressing shoulder 96, ofeach press jaw 66 runs spirally with respect to the press axis x of thepress opening 78. In this connection, the pressing blade 92 and theassociated pressing shoulder 96 of each press jaw 66 extend over acircumferential angle of 120° of the pressed preform 84 between the twoends of the same. Half the circumferential angle α/2 extends in eachcase over 60° in the present case in a symmetrical or complementaryfashion on both sides of the longitudinal mid-axis y of each press jaw66, so that the press jaw 66 is loaded uniformly over its entire crosssection by the pressing forces exerted.

The pressing blades 92 and pressing shoulders 96 of each press jaw 66are not only curved spirally in the longitudinal direction correspondingto the described circumferential angle α of the tampon 30 of 120°, butalso have a curvature 102 (FIGS. 10 and 11) from one end of the pressjaw 66 to the other end of the same press jaw 66. This curvature 102ensues from the fact that the effective pressing surface 90 of eachpress jaw 66 has to press a spiral longitudinal groove 42 which must ineach case extend over a specific circumferential angle of the preform84, that is to say in the present case over 120° of the circumferentialsurface of the approximately cylindrical tampon blank 55 at a specificangle of inclination β (FIG. 3). In this connection, the tampon blank 55(FIG. 7) is as a whole compressed to the pressing dimension d of thepreform 84 (FIG. 11), at which each pressing blade 92 is moved beyondthe position which is radial with respect to the press axis x. As aresult, the clear cross section of the press opening 78 formed by thepress jaws 66 widens from both its ends to the longitudinal center ofthe press jaws 66 or of the press opening 78 formed by these, whichconsequently assumes a barrel shape in the pressing dimension d or inits pressing position. The envelope surface 104 touching the pressingblades 92 or the pressing shoulders 96 therefore has a slightlybarrel-like contour (see FIGS. 5 and 11) which therefore narrows towardboth ends of the press opening 78. Accordingly, the preform 84 alsoassumes a corresponding shape in the press 64, as can be seen from FIGS.5 and 11. In order that the preform 84 can be ejected perfectly, that isto say without damage to the fibrous structure on its surface, from thepress 64 while being rotated about its longitudinal axis, the press jaws66 have to be raised by a specific dimension d+(FIG. 12). This clearancedimension d+ corresponds at least to the radial distance which separatesa chord A, which interconnects the two ends of the pressing blade 92 ofa press jaw 66 in FIG. 11 and runs parallel to the press opening 78,from a tangent B in FIG. 11, which is placed against a vertex 0° of theradially outwardly arcuate curvature 102 of a pressing blade 92 and islikewise oriented parallel to the press opening 78. In addition, theclearance dimension d+ can be defined in such a way that it mustcorrespond at least to the greatest diameter of the barrel-shapedenvelope surface 104, which is touched by the pressing blades 92 orpressing shoulders 96 in the pressing position. In the case of a tampon30 with a diameter of 13 mm, this clearance dimension=d+0.6 mm, by whichthe press jaws 66 must be moved radially outwardly in order to form,according to FIG. 12, the circularly cylindrical envelope surface 106 ofthe press opening 78. In this connection, the pressing blades 92 orpressing shoulders 96 touch the circularly cylindrical envelope surface106 spirally over essentially the entire length in the clearancedimension d+ and consequently form a circularly cylindrical pressopening 78 for the ejection of the preform 84.

FIGS. 7 and 8 show clearly that the neck-shaped contraction 122 of eachpressing blade 92 brought about by the drop shape makes possible agreater displacement of the fibrous material approximately radiallyoutwardly during pressing. As a result, the pressing dimension of thepress jaws 66 can be reduced to, for example, 4 mm from previously 4.8mm of the diameter of the fiber core 38 with the same stability andimproved absorption capacity and with the soft surface of the tampon 30being preserved. Furthermore, the width of the rounded pressing edge 94can be reduced, in order to make it possible for the fibrous material toflow into the radially outwardly created free space of the press opening78. In this way, the quantity of fiber necessary for producing the fibercore 38 can be reduced in favor of that quantity of fiber which, withthe same stability of the tampon, is available for immediate liquidabsorption after introduction of the tampon into the body cavity.

In order to be capable of receiving the outwardly displaced fibrousmaterial, the pressing shoulder 96 has a reduced shoulder radius of 6.2mm in the present illustrative embodiment, compared with 6.55 mmpreviously, and extends in profile approximately parallel to that sideof the press jaw 66 oriented counterclockwise, which merges into theshort L-leg 114 and forms the striking head 116.

The outward displacement of the fibrous material achieved by means ofthis shape of the press jaws 66 makes possible a saving of fibrousmaterial which, in the illustrative embodiment described of a digitaltampon 30 with a final diameter of 13 mm and a length of 50 mm.

It can be seen in particular from FIGS. 9 and 10 that at least onesqueezing rib 120 is provided on an outer side of the pressing shoulder96 approximately at the level of the latter. In the closed state(pressing dimension d) of the press 64, this squeezing rib 120 of thepressing shoulder 96 and also the striking head 116 of each press jaw 66bear against the rounded striking recess 118 of the adjacent press jaw66 in front of the neck-shaped contraction 122 of the pressing blade 92(FIGS. 7 and 8). The outer side of each pressing shoulder 96 is providedin FIGS. 9 and 10 with two parallel squeezing ribs 120 which close a gap124 oriented approximately radially with respect to the press axis xbetween the striking head 116 and the striking recess 118 of adjacentpress jaws 66 in relation to the press opening 78 and thus in each casein relation to the radially outer side of a spiral longitudinal rib 40of the preform 84. As a result, the penetration of fibrous material ofthe tampon blank 55 into the gap 124 between adjacent press jaws 66 isessentially precluded. In the event that fibers penetrate the gap 124between adjacent press jaws 66, the squeezing ribs 120 cut the staplelength of these fibers, so that the fiber residues can fall out of thepress 64 and be extracted by suction. A burr-free, smooth, soft,radially outer surface of each spiral longitudinal rib 40 isconsequently formed.

FIGS. 9 and 10 show clearly that at one end face the striking head 116protrudes further radially inwardly than the pressing blade 92 which isset back by the width of the pressing shoulder 96 with respect to thestriking head 116 and is angled in relation to the latter toward theside facing away from the striking head 116. By means of the side walls86, 88, the press jaws 66 have a cross section normal to theirlongitudinal mid-axis y which has a shape which is complementary to thecircumferential angle α of the spiral press jaw curvature 102, so thatthe abovementioned uniform distribution of the pressing forces exertedin each case by the press jaws 66 over their entire cross section, thatis to say in the direction of the longitudinal mid-axis y of the pressjaws 66, is guaranteed.

FIG. 11 illustrates the pressing dimension d of the press 64diagrammatically. This pressing dimension d corresponds to thebarrel-shaped envelope surface 104 which is formed by the spiralpressing blades 92 and pressing shoulders 96 of the press jaws 66 of thepress 64 in the closed state or pressing dimension d. This pressingdimension d is, depending on the particular composition and purpose ofthe tampon 30 concerned, between 6 and 17 mm, 13 mm in the presentillustrative embodiment, at the inlet end and at the outlet end of theclosed press 64.

During ejection of the preform 84 from the press 64 in this pressingposition shown in FIG. 11, the ejection forces would increase greatly asa result of the barrel-shaped cross section of the press opening 78 andof the preform 84 situated therein. The fibers on the surface of thepreform 84 would be torn out of the fiber composite, the smooth surfaceof the preform 84 would be correspondingly damaged and a fiber losswould be caused. For this reason, provision is made that, after theopening of the press 64 to the given clearance dimension d+, theimaginary envelope surface 106 formed or touched by the pressing blades92 or the pressing shoulders 96 is circularly cylindrical, so that thepreform 84 can be ejected from the press 64, virtually without anyappreciable resistance, through the final shaping tool 68 into thetransport sleeve 74 with simultaneous rotation as a result of the spiralpressing blades 92 engaging in the longitudinal grooves 42 of thepreform 84.

In FIG. 12, the spiral pressing blades 92 and pressing shoulders 96 ofthe press jaws 66 have been moved back radially outwardly by a givenclearance dimension d+ of, in the present illustrative embodiment, d+0.6mm in relation to the pressing dimension d shown in FIG. 11, in order toenclose or touch the imaginary circularly cylindrical envelope surface106, which allows the preform 84, which has been pressed in a barrelshape and provided with spiral longitudinal ribs 40 and spirallongitudinal grooves 42, to be pushed out of the press 64 withsubstantially reduced friction by means of the ejector 82 in the feedpusher 76.

According to FIG. 12, the pressing blades 92 and the pressing shoulders96 of all the press jaws 66 therefore each touch the imaginary,circularly cylindrical envelope surface 106 on a spiral line over atleast a considerable part of their length. That is to say if a lowerdegree of compression of the fibrous material is desired at the recoveryend 34 of the preform 84, the radial distance of the effective pressingedges 94 from the press axis x in the area of the outlet side 79 of thepress opening 78 is dimensioned to be somewhat greater, in the closedstate of the press jaws 66, than over the remaining longitudinal area ofthe pressing edges 94, so that this part of the pressing edges 94 wouldnot touch the circularly cylindrical envelope surface 106 in theclearance dimension d+ of the press jaws 66 but would lie slightlyradially outside this circularly cylindrical envelope surface 106.

FIGS. 13 and 14 show an embodiment of a press 130 with multi-part pressjaws 132. The divided press jaws 132 can be moved to and fro radiallywith respect to the press axis x independently of one another. The pressjaws 132 are divided in at least one plane T which is oriented at rightangles to the press axis x. In the present illustrative embodiment, thepress jaws 132 are of two-part design. The dividing plane T of thetwo-part press jaws 132 a, 132 b intersects the 0° vertex of theirpressing surface 134 and the axis x of the press 130, at thelongitudinal center M of the same. The press-jaw halves 132 a associatedwith the outlet side 79 of the press 130 can be moved radially outwardinto the clearance position d+ from their pressing position d inrelation to the press axis x in order to make possible ejection of thepreform 84 from the press (FIG. 14) with greatly reduced friction. Bymultiple division of the press jaws 132 transversely to the press axis xand depending on the number of press jaws 132, the circumferential angleα can be extended beyond 150°. Furthermore, suitable design of the pressjaws also makes it possible to modify the outer contour of the tampondepending on the specific tampon requirements.

From the above description of the press jaws 66; 132 according to theinvention, it is preferred that the press jaws lie diametricallyopposite one another in pairs. The present invention also includes thepossibility of, in addition to the press jaws 66; 132 described, whichproduce the fiber core 38, building press jaws into the press 64; 130which serve purposes other than the production of the fiber core 38.Accordingly, it is possible to use press jaws within the press 64; 130in order, for example, to stamp patterns or depressions onto or into thesurface of the tampon 30 during pressing of the preform 84, which areintended to serve decorative and/or physical purposes.

FIGS. 15, 16 and 17 show the final shaping tool 68, which consists of aguide plate 140 which is arranged in a stationary manner immediatelybehind and coaxially with the press 64 and is designed in one piece witha smoothing bush 150 for the preforms 84. The final shaping tool 68includes a conical final shaping channel 152 for the preforms 84, whichextends through the guide plate 140 and the smoothing bush 150. As shownin FIG. 5, the guide plate 140 is arranged immediately in front of theoutlet side 79 of the press 64 and, as already described in U.S. Pat.No. 5,911,712, is provided on its side facing the press 64 with a numberof grooves 142 corresponding to the number of press jaws 66; 132, whichare arranged at the same circumferential angle intervals as the pressjaws 66; 132. According to the invention, the grooves 142 extend at adistance from and parallel to the press jaw axis y in the direction ofthe press opening 78 tangentially with respect to the final shapingchannel 152.

It can be seen from FIGS. 5 and 9 to 14 that the press jaws 66; 132 areeach provided at their rear end with a positioning web 160 whichprojects with respect to the outlet side 79 of the press 64 and in eachcase engages in one of these grooves 142 with lateral play. The inner,free front end of the positioning webs 160 is a component of thepressing surface 90; 134 of the press jaws 66; 132 and reaches over anaxial gap between the press 64; 130 and the final shaping tool 68. Intheir clearance position d+, the pressing surfaces 90; 134 of the pressjaws 66; 132 have a slightly smaller diameter than the inlet opening 154of the smoothing bush 150. This allows the positioning webs 160 tomaintain the centered position of the recovery tape 35 (previously woundspirally at the recovery end 34 of the tampon blank 55 lying at thefront in the transport direction x (FIGS. 16, 17)) during the pressingand the ejection of the tampon 30 from the press 64. From the circularinlet opening 154, the final shaping channel 152 tapers conically to anoutlet opening 156 of the smoothing bush 150. In this connection, theconical shape of the smoothing bush 150 is designed in such a mannerthat as small as possible an ejection force is necessary in order topush the preform 84 out of the press 64 through the smoothing bush 150and to compress it concentrically to the final dimension of the tampon30.

FIGS. 5 and 14 to 16 show that the final shaping tool 68 is providedwith spirally shaped, radially inwardly projecting smoothing ribs 170,the number of which corresponds to that of the press jaws 66 and theangle of inclination β of which corresponds to that of the spiralpressing blades 92. The spiral smoothing ribs 170 engage directly in alightly concentrically pressing and smoothing manner in the spirallongitudinal grooves 42 of the preform 84 leaving the press 64, so thatthe profile of the preform 84 is preserved but the widening of the crosssection of the fiber core 38 caused by the barrel shape of the preform84 is reduced. The smoothing bush 150 can be heated to a temperature of80° to 120° C. in order, if desired, to optimize the smoothing effect.The smoothing ribs 170 end at a distance in front of the outlet opening156 of the smoothing bush 150 and merge into a smooth cylindrical endsection 172 of the smoothing bush 150. This end section 172 of thesmoothing bush 150 has a diameter which corresponds to the diameter ofthe finished pressed tampon 30. In this smooth cylindrical end section172 of the smoothing bush 150, the spiral longitudinal grooves 42 of thepreform 84, which were open up to here, are closed at the radially outerends of the side flanks 44 of adjacent spiral longitudinal ribs 40 tothe final diameter of the tampon 30 (FIG. 4). In this way, thelongitudinal grooves 42 become the liquid guide ducts 50 which arepreferably open toward both ends of the tampon 30 (FIGS. 3 and 4).

In FIGS. 5, 14 and 15, the transport apparatus 70 is illustrated in anessentially cut-away manner and consists in the present case, as part ofa circulating or rotating transport system, of a revolver 72. Therevolver 72 is provided with a transverse hole 148, in which thecylindrical transport sleeve 74 fits and is fixed at right angles to thecirculating plane of the revolver 72. The transport sleeves 74 are fixedto the revolver 72 at equal circumferential angle intervals and radii,so that in each case one transport sleeve 74 can be moved successivelystep by step in front of the outlet opening 156 of the smoothing bush150, in order to feed a finished pressed tampon 30 to a furtherproduction station. In this production station (not shown), as is knownper se, the insertion end 32 can be provided with the round dome 52 atthe same time as the recovery end 34 is provided with the finger recess48.

As the tampon 30 is subjected to rotation by the spiral press jaws 66and the spiral smoothing ribs 170 in one single operation on ejectionfrom the press 64 through the smoothing bush 150 into the transportsleeve 74, the cylindrical transport sleeve 74, which is widenedconically over a short length at its inlet opening, ensures that thehigh quality of the surface and of the fibrous structure of the tampon30 is preserved. In this connection, this delayed laying of the tampon30 against the cylindrical inner wall of the transport sleeve 74 iscaused by the expansion of the fibrous material of the finished pressedtampon 30, that is to say that the diameter of the transport sleeve 74is dimensioned to be correspondingly greater so as to allow for thisexpansion of the fibrous material of the tampon 30 immediately afterpressing. This is because a positive contact of the tampon 30 againstthe cylindrical smooth inner wall of the transport sleeve 74 takes placeonly, as a result of its expansion after pressing, when the tampon 30concerned has, with its recovery end 34 lying at the front, almost orcompletely left the outlet opening 156 of the smoothing bush 150.

Furthermore, it can be seen in FIG. 16 that the outlet-side spiralpressing edges 94 of the press jaws 66, which edges lie opposite oneanother in pairs, form an angle which widens to the outlet end 79 of thepress 64. As a result, the fiber core 38 is more weakly pressed at therecovery end 34 of the preform 84, so that the fibrous material can bespread slightly before use so as to facilitate digital introduction ofthe tampon.

In FIG. 17, the incipient expansion of the tampon 30 and its resultingcontact against the cylindrical inner wall of the transport sleeve 74 atF is shown especially clearly owing to the enlarged illustration. Thefact that the tampon 30 expands only once it is in the transport sleeve74 on account of the memory effect of the greatly expanding fiberproportion, can be attributed to the high production speed of thetampon. Associated with this is the considerable advantage that therotary movement to which the tampon 30 is subjected during ejectionencounters no appreciable resistance, so that the spiral fibrousstructure of the tampon achieved by the invention is preserved in itsfull extent.

The method of producing the tampon according to a preferred embodimentof the invention comprises the steps:

-   -   providing a tampon blank of tangled fibrous material;    -   compressing the tampon blank on narrow generating lines of its        circumferential surface, which are separated from one another by        equal circumferential angles, forming longitudinal grooves and a        substantially cylindrical fiber core with a high degree of        compression, from which relatively uncompressed longitudinal        ribs extend radially outward, the tampon blank being pressed on        spiral generating lines in order to form spiral longitudinal        grooves and spiral longitudinal ribs parallel thereto in order        to enlarge the absorbent surface of the tampon.

In detail, the preferably cylindrical tampon blank 55, the recovery end34 of which lies at the front in the feed direction or in the directionof the press axis x, is then introduced coaxially into the press 64 bymeans of the feed pusher 76. Subsequently, the tampon blank 55 isradially compressed by the press jaws 66 in the press 64 in each caseover identical, narrow, spirally shaped sections of identical angle ofinclination β of its circumferential surface, which sections areseparated from one another by equal circumferential angles. In this way,a preform 84 of preferably barrel-shaped contour is produced, withspirally running longitudinal grooves 42 on a solid fiber core 38 with ahigh degree of compression which is substantially cylindrical but,because of the barrel shape, is widened in cross section at mid-length,and with longitudinal ribs 40 which extend radially outwardly from thefiber core 38 and run spirally in the longitudinal direction of thepreform 84. In this connection, the spirally shaped sections are in eachcase pressed over a circumferential angle α of up to at least 150°,preferably over an angle of 80° to 120°, in the present case over anangle of 120°. In the press 64, the fibrous material is preferablysubjected to lower radial compressing pressure in the area of therecovery end 34 of the tampon blank 55 than the remaining fibrousmaterial of the tampon blank 55. The tampon blank 55 is, depending onthe properties of the fibrous material used, in particular in the eventof use being made of highly expansive fibers of irregular cross sectionwith a strong memory effect, pressed at a temperature of the press jaws66 of 80° to 120° C. to the final shape of the tampon 30, in order toachieve the desired dimensional stability of the fibrous material byeliminating the memory effect of the fibers, which immediately becomeseffective again on contact with bodily fluid and thus increases theexpansion and absorption speed of the tampon 30 with the least possibleuse of fibrous material.

In the press 64; 130, the tampon blank 55 is compressed in a singlepressing operation to form the barrel-shaped preform 84 which, onejection from the press 64, may be at the same time subjected to finalshaping in the downstream, if appropriate heatable, smoothing bush 150.This final shaping includes a weak radial pressure being exerted on theouter ends of the spiral longitudinal ribs 40 and on the spirallongitudinal grooves 42 by the smoothing bush 150, which can be heatedto 80° C. to 120° C. if so desired, and its smoothing ribs 170. Thisweak radial pressure has the effect that the outer ends of the mutuallyopposite side flanks 44 of adjacent longitudinal ribs 40 are pressedagainst one another by the smooth, circular cross section of the finalshaping channel 152 in the area of the outlet opening 156 of thesmoothing bush 150, so that the longitudinal grooves 42 and thus theouter, approximately cylindrical, soft, closed circumferential surface46 of the tampon 30 are shaped, and the spiral liquid guide ducts 50 areproduced in the area of the now radially outwardly closed longitudinalgrooves 42, which ducts are preferably open at the insertion end and atthe recovery end of the tampon. In this way, a considerable increase inthe absorption capacity of the tampon is achieved along with verycomfortable introduction for the user. Furthermore, the smoothing ribs170 may reduce slightly the cross-sectional widening of the fiber core38 caused by the barrel shape of the preform 84 of this embodiment.

On the exit, associated with the rotary movement, of the finishedpressed tampon 30 from the smoothing bush 150 into the transport sleeve74 of the transport apparatus 70, the newly compressed fibrous materialexpands in relation to the very smooth, cylindrical inner wall of thetransport sleeve 74, without frictional resistance, which would impairthe surface quality, occurring between the cylindrical, smooth innerwall of the transport sleeve 74 and the fibrous material on the surfaceof the tampon 30, so that the high quality of this tampon 30 providedwith spiral longitudinal ribs 40 and longitudinal grooves 42 is ensuredeven in the case of mass production. In this connection, it is importantthat the direction of rotation, in which the length of a fibrousnonwoven, at the end of which a sheathing material is fixed on theoutside, is wound up to form a tampon blank 55, is also maintained bythe spiral press jaws and smoothing ribs, in order that the embedding ofthe free, outer end of the sheathing material strip in the surface ofthe tampon 30 is maintained.

The specification and embodiments above are presented to aid in thecomplete and non-limiting understanding of the invention disclosedherein. Since many variations and embodiments of the invention can bemade without departing from its spirit and scope, the invention residesin the claims hereinafter appended.

What is claimed is:
 1. A method of producing a tampon, comprising thesteps: providing a tampon blank of tangled fibrous material having alongitudinal axis; compressing at least narrow lines of an outercircumferential surface of said tampon blank to form a compressed tamponhaving longitudinal grooves that are at least partially spirally shapedhaving an insertion end and a recovery end.
 2. The method of claim 1,wherein said tampon blank is compressed radially with respect to saidlongitudinal axis.
 3. The method of claim 1, wherein said tampon blankis compressed such that said fibrous material of said tampon has anessentially uniform density over a cross-section of said tampon.
 4. Themethod of claim 1, wherein the tampon blank is compressed such that saidtampon further comprises a core with a high degree of compression fromwhich relatively uncompressed longitudinal ribs extend radially outward.5. The method of claim 4, wherein said tampon blank is compressed suchthat said longitudinal ribs are at least partially relativelyuncompressed compared with said core.
 6. The method of claim 4, whereinsaid tampon blank is compressed such that said longitudinal ribs extendradially outward at equal circumferential angle intervals and betweensaid insertion end and said recovery end.
 7. The method of claim 6,wherein said tampon blank is pressed to form said tampon having a fibercore, and the circumferential surface of said fiber core of said tamponare curved radially outwardly in a barrel-shaped manner.
 8. The methodof claim 6, wherein said tampon blank is pressed to form said tamponhaving a fiber core, and said circumferential surface and said fibercore of said tampon are substantially cylindrical.
 9. The method ofclaim 1, wherein said narrow lines of compression are each pressed overa circumferential angle of up to at least about 150 degrees of saidtampon blank.
 10. The method of claim 9, wherein said narrow lines ofcompression are each pressed over a circumferential angle of about 80degrees to about 120 degrees.
 11. The method of claim 1, wherein saidtampon blank is compressed at room temperature.
 12. The method of claim11, wherein said tampon blank is compressed at a temperature of about 80degrees Celsius to about 120 degrees Celsius.
 13. The method of claim 6,wherein after said pressing of said spiral longitudinal grooves,radially outer ends of said longitudinal ribs are simultaneouslysubjected to a slight concentric pressure, so that ends of opposite sideflanks of adjacent spiral longitudinal ribs are laid on one another andform a soft, closed circumferential surface of said tampon, said spirallongitudinal grooves on the outer circumferential surface of said tamponbeing closed to form liquid guide ducts defined by said longitudinalgrooves.
 14. The method of claim 6, further comprising smoothing saidspiral longitudinal ribs and said spiral longitudinal grooves beforebeing pressed to a final shape of said tampon.
 15. The method of claim14, wherein said smoothing is carried out at about 80 degrees Celsius toabout 120 degrees Celsius.
 16. A method of producing a tampon,comprising the steps: providing a tampon blank of tangled fibrousmaterial having a longitudinal axis; compressing at least narrow linesof an outer circumferential surface of said tampon blank to form acompressed tampon having longitudinal grooves and longitudinal ribsadjacent to said longitudinal grooves, said longitudinal ribs extendingradially outward from said tampon blank, said longitudinal grooves andsaid longitudinal ribs are at least partially spirally shaped, eachhaving an insertion end and a recovery end.
 17. The method of claim 16,wherein said tampon blank is radially compressed by a press having pressjaws.
 18. A method of producing a tampon, comprising the steps:providing a tampon blank of tangled fibrous material having alongitudinal axis; compressing at least one narrow line of an outercircumferential surface of said tampon blank to form a compressed tamponhaving at least one longitudinal groove and at least one longitudinalrib adjacent said at least one longitudinal groove, said at least onelongitudinal rib extending radially outward from said tampon blank, saidat least one longitudinal groove and said at least one longitudinal ribare each at least partially spirally shaped, each having an insertionend and a recovery end, wherein said circumferential surface is enlargedafter said at least one longitudinal groove and at least onelongitudinal rib are formed by compression.
 19. The method of claim 18,wherein said tampon blank is radially compressed by a press having atleast one press jaw.